Synonym of PRECARIOUS

Answer: Option B

Brittle : hard but liable to break easily.
Perilous : full of danger or risk.
Critical : expressing adverse or disapproving comments or judgements.
Cautious : (of a person) careful to avoid potential problems or dangers.
Precarious : not securely held or in position; dangerously likely to fall or collapse.

Synonym of Precarious is Perilous